This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. -Background and Aim Hepatitis C Virus (HCV) is known to establish a lifelong persistent infection causing patient a chronic inflammatory disease, which eventually results in severe complication of liver diseases including fibrosis, cirrhosis and hepatocellular carcinoma. As the sole member of the genus Hepacivirus of Flaviviridae family, this ssRNA virus of plus strand polarity replicates in the cytosolic compartment of infected cells and causes an altered membraneous structure called "membraneous web" which is believed to be extended from rough endoplasmic reticulum, and is associated with actively replicating viral RNA. Although little is known about how this virus establish their microenviroment inside cell, It is becoming of great interest to reveal how HCV is dealing with both lipid metabolism and its trafficking in the context of their demand for virion production as envelope virus. -Method Human hepatoma cell line, Huh-7 was transfected with subgenomic replicon RNA, into which Affinity-tag peptide sequence was introduced in the C-terminus region of Nonstructural protein 5A (NS5A). Transfected cells were cultured with G418 supplemented media in order to select cells harbouring replicating viral RNA. Resultant G418-resistant cells were isolated and were found to be expressing affinity-tagged NS5A protein via viral replication. Viral protein complex as well as their interacting host proteins were isolated by affinity-culumn purification and analized by MudPIT in order to identify associating host factors.